The drop jump is an advanced plyometric exercise designed to increase explosive power and reactive strength for activities like jumping and sprinting. It is not a foundational movement, but a specialized method for enhancing the body’s ability to absorb and rapidly produce force. This exercise trains the body to convert the potential energy from a drop into a powerful upward jump.
Executing the Drop Jump
Proper execution begins by selecting a plyometric box and standing on the edge with feet shoulder-width apart. The movement is initiated by stepping off the platform, not jumping down. The goal is to use the momentum from the fall to load the muscles, so the drop should be controlled, allowing gravity to pull the body toward the ground in a straight line.
Upon approaching the ground, land on the balls of the feet with a slight bend in the knees and hips. The landing should be as quiet and brief as possible to minimize ground contact time. This requires the muscles of the lower body, including the calves, quadriceps, and glutes, to tense immediately upon impact to stabilize the joints.
The instant the feet touch the ground, reverse the downward motion into an explosive, maximal vertical jump. The arms should swing upward forcefully to contribute to the ascent’s momentum. A common mistake is to pause after landing or sink into a deep squat, which dissipates the stored energy and defeats the purpose of the exercise.
Two primary techniques exist: the bounce drop jump and the counter-movement drop jump. The bounce technique focuses on the quickest possible reversal of momentum with minimal knee bend and ground time. The counter-movement style involves a slightly deeper landing to emphasize different aspects of muscle coordination. For most athletic purposes focused on enhancing reactive power, the bounce technique is preferred because it generates higher forces in the knee and ankle joints.
The Underlying Biomechanics
The effectiveness of the drop jump is rooted in the stretch-shortening cycle (SSC). The SSC allows muscles to produce more force during a shortening (concentric) contraction if it is immediately preceded by a lengthening (eccentric) contraction. This process is like stretching a rubber band before letting it go; the pre-stretch stores elastic energy that is released for a more powerful snap.
The drop jump has three phases corresponding to the SSC. The first is the eccentric phase, as the athlete drops and the leg muscles lengthen to absorb the landing’s impact. During this phase, elastic energy is stored in the muscle and tendon structures. The quadriceps, glutes, and calves are engaged to control the descent.
The second stage is the amortization phase, the brief period between landing and jumping. The goal is to make this phase as short as possible. A shorter amortization phase means less stored elastic energy is lost as heat, allowing for a more powerful concentric contraction. This phase trains the neuromuscular system to rapidly transition from absorbing force to producing it.
Finally, the concentric phase is the explosive vertical jump. During this phase, the stored elastic energy from the eccentric loading is released, augmenting the force generated by the muscular contraction. This results in a jump that is more powerful than what could be achieved from a static start.
Implementing Drop Jumps in Training
The height of the drop is a primary factor in training. Beginners should start with a low box, between 30 to 45 centimeters (12 to 18 inches), to master the technique. The optimal drop height allows for the shortest ground contact time without a decrease in jump height. Increasing the drop height beyond 60 centimeters (about 24 inches) often increases ground contact time without improving performance.
The volume of drop jumps should be low, emphasizing quality over quantity. A common prescription is 3 to 5 sets of 3 to 5 repetitions. This low volume ensures that each jump can be performed with maximal intensity and proper form. Because the exercise is demanding on the central nervous system, rest for 2 to 3 minutes between sets to allow for recovery.
Drop jumps should be performed early in a workout, after a thorough warm-up but before heavy strength training or conditioning. Performing them while fatigued increases the risk of injury and diminishes the training effect. This placement ensures the nervous system is fresh for the required high-quality movements.
An athlete should have a solid foundation of strength before incorporating drop jumps. A general guideline is the ability to squat at least 1.5 times one’s body weight. This prerequisite strength ensures the body is prepared to handle the high-impact forces and reduces the risk of injury to the knees, ankles, or lower back.